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1.
To provide sustainable income from forestlands, large areas in the tropics are planted with “agricultural” trees, such as oil palm and rubber, and “industrial” trees, such as Acacia mangium and Gmelina arborea. To examine how native forest birds use such plantations, we surveyed in 2005 the avifauna at Sabah Softwoods, a plantation in southeastern Sabah, Malaysian Borneo. We focused on A. mangium, Albizia (Paraserianthes falcataria), oil palm (Elaeis guineensis), and logged native forest, and compared our results to those of a study conducted at the same plantation in 1982. The number of forest species in the industrial groves did not change dramatically between 1982 and 2005, even though the trees had been cropped several times and the plantation was, by 2005, completely surrounded by cleared land and far removed from primary forest. However, as is common in logged or isolated forests throughout the world, certain primary forest groups (e.g., muscicapine flycatchers) have been extirpated from the entire plantation area. The industrial groves also lacked some larger species of kingfisher, woodpeckers, and canopy frugivores. Nevertheless, numerous primary forest taxa (ca. 50% of species) were found in mature industrial tree groves. Albizia attracted the most species of birds, followed closely by Acacia. Both tree types underpinned relatively complex secondary forests that attracted forest birds. In contrast, younger groves of Acacia and Albizia held mainly open country and scrub species. Oil palm, as a remarkably simple and unusual habitat, attracted few bird species. Sustained occurrence of forest birds in all groves of exotic trees at Sabah Softwoods was substantially enhanced by the relatively rich avifauna of the logged native forest remaining in substantial stands throughout the plantation.  相似文献   

2.
Changes in soil carbon (C) from forest to agriculture land in Mukah, Sarawak, and Simpang Renggam (SR) Johor were studied. The changes in labile C (CL) (Mukah, 0.7–43%; SR, 0.2–20%) were greater than changes in the total C (CT) (Mukah, 0.5–9%; SR, 0.3–7%) as compared to the forest. In Mukah, oil palm and pineapple ecosystems showed approximately 18% and 6% increases in CL at a soil depth of 0–15 cm, respectively, as compared to the forest, and thus had greater C management index (CMI) values. In the sago ecosystem, the decline in CL was approximately 26% at the soil depth of 0–15 cm as compared to the forest. In SR, oil palm and pineapple ecosystems showed approximately 0.2% and 19% decreases in CL, respectively, at soil depths of 0–15 cm, resulting in low CMI value. The CL and the CMI can be used to monitor the rate of changes in soil C for different land uses on peat.  相似文献   

3.
The land competition between tropical bioenergy plantations and payments for forest carbon conservation (e.g., through an international scheme for Reduced emissions from deforestation and forest degradation, REDD+) is modeled using spatially explicit data on biofuel feedstock (oil palm and sugar cane) suitability and forest biomass carbon stocks. The results show that a price on the (avoided) carbon emissions from deforestation at the same level as those from fossil fuel use makes clearing for high yielding bioenergy crops unprofitable on about 60% of the tropical evergreen forest area. For the remaining 40% deforestation remains the most profitable option. Continued profitability of forest clearing is most pronounced for oil palm bioenergy systems in Latin America and Africa, with REDD+ making deforestation for sugar cane plantations unprofitable on 97% of evergreen forest land. Results are shown to be relatively robust to assumptions regarding potential yields and to the addition of a ‘biodiversity premium’ on land use change emissions. While REDD+ may play an important role in stemming biodiversity loss and reducing carbon emissions from tropical deforestation in the near future, in the longer run reliance on a system that values forests solely for their carbon retention capacities poses a serious risk. It is imperative that the institutions and policies currently being established as part of REDD+ readiness activities are resilient to future changes in the incentive structures facing tropical forest countries due to, e.g., climate policy induced demand for biofuels.  相似文献   

4.
La Campana, a new Chilean national park, includes examples of all the major biotic communities of central Chile: Nothofagus forest, hygrophilous forest, sclerophyll forest, matorral, bamboo thicket, succulent scrub, high altitude communities, and palm forest. Although the exact boundaries have yet to be determined, the park includes approximately 15,000 ha, and lies less than 75 km from both Santiago and Valparaiso. The unique natural features of the park are discussed and the current movement to support its development are described.  相似文献   

5.
《Applied soil ecology》2007,35(2-3):258-265
We examined the relationship between soil respiration rate and environmental determinants in three types of tropical forest ecosystem—primary forest, secondary forest, and an oil palm plantation in the Pasoh Forest Reserve on the Malaysian Peninsula. In August 2000, the soil respiration rate and environmental factors (soil temperature, soil water content, soil C and N contents, biomass of fine roots, and microbes) were measured at 12–16 points in research quadrats. Soil respiration rates were 831 ± 480, 1104 ± 995, 838 ± 143, 576 ± 374, and 966 ± 578 (mean ± S.D.) mg CO2 m−2 h−1 in the primary forest canopy and gap site, secondary forest canopy and gap site, and oil palm plantation, respectively. Although the mean soil respiration rates in the three forest ecosystems did not differ significantly, differences were evident in the environmental factors affecting the soil respiration. The major causes of spatial variation in soil respiration were fine root biomass, soil water content, and soil C content in the primary and secondary forests and oil palm plantation, respectively.  相似文献   

6.
Abstract

Nitrous oxide (N2O) emissions were measured monthly over 1 year in three ecosystems on tropical peatland of Sarawak, Malaysia, using a closed-chamber technique. The three ecosystems investigated were mixed peat swamp forest, sago (Metroxylon sagu) and oil palm (Elaeis guineensis) plantations. The highest annual N2O emissions were observed in the sago ecosystem with a production rate of 3.3 kg N ha?1 year?1, followed by the oil palm ecosystem at 1.2 kg N ha?1 year?1 and the forest ecosystem at 0.7 kg N ha?1 year?1. The N2O emissions ranged from –3.4 to 19.7 µg N m?2 h?1 for the forest ecosystem, from 1.0 to 176.3 µg N m?2 h?1 for the sago ecosystem and from 0.9 to 58.4 µg N m?2 h?1 for the oil palm ecosystem. Multiple regression analysis showed that N2O production in each ecosystem was regulated by different variables. The key factors influencing N2O emissions in the forest ecosystem were the water table and the NH+ 4 concentration at 25–50 cm, soil temperature at 5 cm and nitrate concentration at 0–25 cm in the sago ecosystem, and water-filled pore space, soil temperature at 5 cm and NH+ 4 concentrations at 0–25 cm in the oil palm ecosystem. R2 values for the above regression equations were 0.57, 0.63 and 0.48 for forest, sago and oil palm, respectively. The results suggest that the conversion of tropical peat swamp forest to agricultural crops, which causes substantial changes to the environment and soil properties, will significantly affect the exchange of N2O between the tropical peatland and the atmosphere. Thus, the estimation of net N2O production from tropical peatland for the global N2O budget should take into consideration ecosystem type.  相似文献   

7.
ABSTRACT

In Malaysia, soils derived from sedimentary rocks are extensively used for agricultural purposes with oil palm and rubber being the main dwellers. In order to understand the environmental impact of these perennial crops planting, the variability of physicochemical properties of 25 representative soils derived from sedimentary rocks under different ecosystems (agriculture land and natural forest) at six study sites spread across Malaysia was examined. Among the soil physicochemical properties, total soil organic carbon, total nitrogen, and fertility level were found to be generally higher in the forest ecosystems followed by rubber plantation and finally oil palm plantations. Likewise, projection of principal component analysis showed an associative relationship between soil physicochemical properties and microhabitats. Finally, this study showed that soils from different agricultural and natural sites, but derived from similar sedimentary rocks, had distinctive weathering conditions and soil properties. Therefore, site-specific field management according to soil type, soil management techniques as well as fertilizer strategies are required to maximize crop production and to sustain ecosystem services. The output of this study will enable farmers to improve their crop yield via the selection of suitable crops cultivation based on soil characteristics.  相似文献   

8.
To conserve tropical forests, it is crucial to characterise the disturbance threshold beyond which populations of tropical trees are no longer resilient. This approach is still not widely employed, especially with respect to the effects of moderate disturbances. Compensation effects, such as positive interactions among plants, are addressed even more rarely. We attempt to identify the extents to which the distribution of the keystone palm tree Ceroxylon echinulatum is regulated by various regimes of deforestation in a threatened tropical montane cloud forest in the North-West Andes of Ecuador. The demographic structure of this palm tree was examined in three habitats: old-growth forest, forest disturbed by selective logging, and deforested pasture. Patterns were related to stand structure, microclimate, and soil composition. Seedling desiccation owing to severe aboveground water stress led to the absence of juvenile palms in pastures, and thus was predictive of a near extinction of the species in this habitat. However, shade provided by dominant bunchgrass in pastures considerably reduced above- and belowground water stress by diminishing light intensity. Selective logging resulted in a higher density of individuals in disturbed forests than in old-growth forests, but was associated with a spoiled spatial structure. Therefore, the protection of residual old-growth forests is a prerequisite for the conservation of C. echinulatum, although secondary forests might act as provisional refuges that promote its resilience. The reduction of water stress by nurse grasses in pastures represents a promising approach to promote the resilience of tropical tree species and their associated communities after deforestation.  相似文献   

9.
The expansion of agricultural plantations at the expense of forest drives dramatic losses of biodiversity and carbon. Consumers are now demanding sustainability in tropical agriculture and producers are responding with questionable certification standards. Many certification schemes—including those for oil palm, soy, sugar cane and cacao—rely upon the High Conservation Value (HCV) concept to prevent unacceptable losses of biodiversity to agricultural conversion. This concept protects very rare species or habitats, exceptional concentrations of wildlife, or large landscape-level areas of forest. Yet much biodiversity persists below these thresholds yielding the spectre of unsustainable conversion of forest to certified plantation crops under a green label. To meet more rigorous standards of sustainability, tropical plantations would have to retain large patches of native forests in the matrix. We highlight six critical areas in need of consideration by conservation scientists, practitioners and certification processes. In particular, the application of HCV to sustainable agricultural development at the national-level, the use of Imperata grasslands and abandoned agriculture, the creation of Biobanks, and increased price premiums for certified crops could redound to the long-term protection of tropical biodiversity.  相似文献   

10.
Organic soils or Histosols or peats as they are commonly referred to, are characterized by the presence of large amounts of organic soil materials (OSM), which is commonly quantified by the Walkley and Black (1934) (WB) method to determine the soil organic matter (SOM) using a correction factor of 1.724. SOM of Histosols is also identified through a combustion (loss on ignition, LOI) or elemental C-analysis (with a carbon-nitrogen-sulfur (CNS) analyzer with combustion and gas density detector). These methods were established using temperate and boreal peat deposits and here we demonstrate that tropical peat deposits require a modified approach. Typical SE-Asian tropical lowland peat pedons from rain forest and oil palm settings were sampled and the material analysed using a CNS analyzer, WB-C and LOI. The ratios for LOI:CNS-C for the 20 samples yielded values between 2.00–3.09 with a mean of 2.50 while the LOI:WB-C ratio yielded values from 1.75 to 2.58 with a mean of 1.94. A comparison of these values for topsoils and subsoils showed mean ratios (LOI:WB-C) of 1.94 and 1.89 for topsoils and subsoils, respectively. The forest samples had higher LOI:WB-C ratios than the subsoils from oil palm settings (1.94 vs 1.84). These values suggest that the standard factor of 1.724 to correct OSM to SOM for tropical soils is untenable. The values to convert CNS and WB-C values of tropical topsoils/subsoils to SOM or LOI should be 2.5 or 1.9, respectively. Our results indicate a significant difference in the soil organic carbon (SOC) of tropical lowland peats depending on the method used.  相似文献   

11.
Methane fluxes were measured monthly over a year from tropical peatland of Sarawak, Malaysia using a closed-chamber technique. The CH4 fluxes in forest ecosystem ranged from −4.53 to 8.40 μg C m−2 h−1, in the oil palm ecosystem from −32.78 to 4.17 μg C m−2 h−1 and in the sago ecosystem from −7.44 to 102.06 μg C m−2 h−1. A regression tree approach showed that CH4 fluxes in each ecosystem were related to different underlying environmental factors. They were relative humidity for forest and water table for both sago and oil palm ecosystems. On an annual basis, both forest and sago were CH4 source with an emission of 18.34 mg C m−2 yr−1 for forest and 180 mg C m−2 yr−1 for sago. Only oil palm ecosystem was a CH4 sink with an uptake rate of −15.14 mg C m−2 yr−1. These results suggest that different dominant underlying environmental factors among the studied ecosystems affected the exchange of CH4 between tropical peatland and the atmosphere.  相似文献   

12.
The establishment of plant species depends crucially on where the seeds are deposited. However, since most studies have been conducted in continuous forests, not much is known about the effects of forest fragmentation on the maintenance of abiotic and biotic characteristics in microhabitats and their effects on seed survival. In this study, we evaluated the effects of forest fragmentation on the predation upon the seeds of the palm Syagrus romanzoffiana in three microhabitats (interior forest, forest edge and gaps) in eight fragments of semi-deciduous Atlantic forest ranging in size from 9.5 ha to 33,845 ha in southeastern Brazil. Specifically, we examined the influence of the microhabitat structure, fauna and fragment size on the pattern of seed predation. Fragments <100 ha showed similar abiotic and biotic characteristics to those of the forest edge, with no seed predation in these areas. Forest fragments 230-380 ha in size did not present “safe sites” for S. romanzoffiana seed survival and showed high seed predation intensity in all microhabitats evaluated. In fragments larger than 1000 ha, the seed predation was lower, with abiotic and biotic differences among gaps, interior forests and forest edges. In these fragments, the survival of S. romanzoffiana seeds was related to squirrel abundance and interior forest maintenance. Based on these results, we concluded that there are no safe sites for S. romanzoffiana seed establishment in medium- and small-sized fragments as result of the biotic and abiotic pressure, respectively. We suggest that on these forest fragments, management plans are needed for the establishment of S. romanzoffiana, such as interior forest improvement and development in small-sized sites in order to minimize the edge effects, and on medium-sized fragments, we suggest post-dispersal seed protection in order to avoid seed predation by vertebrates. Our findings also stress the importance of assessing the influence of forest fragmentation on angiosperm reproductive biology as part of the effective planning for the management of fragmented areas.  相似文献   

13.
To make clear the nutritional characteristics of sago palm (Metroxylon sagu Rottb.) and oil palm (Elaeis guineensin Jacq.) grown in tropical peat soil, minerals concentration, organic compounds concentration, and photo‐synthetic rate were estimated, and the obtained results were as follows. Since, the nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and sodium (Na) concentration in mature leaves and trunk were higher in the oil palm than in the sago palm, but potassium (K) concentration was higher in the sago palm than in the oil palm, the minerals (especially N, P, Ca, and Mg) requirement for the oil palm were higher than in the sago palm. This indicates that the sago palm will adapt better than the oil palm to soils with poor nutrients. The manganese (Mn) and zinc (Zn) concentration in leaves of the sago palm and Ca and aluminum (Al) concentration in leaves of the oil palm increased with the increase of aging, indicating that those elements are eliminated from plants through leaf senescence. In the sago palm, the N and P distribution ratio to leaves remained almost constant during growth, indicating that N and P were predominantly distributed to leaves for maintaining leaf function. The photosynthetic rate [μmole carbon dioxide (CO2) m2 LA sec‐1] at light saturation was lower in the sago palm (5.8) and oil palm (10.0) than in wheat (25.4). As leaf longevity of sago and oil palms was longer (about 12 times) than that of wheat (Triticum aevstium L.), and the minerals concentration and photosynthetic rate remained constant for a long duration of growth, the cumulative carbon (C) accumulation per unit dry weight (photosynthetic rate x leaf longevity) in the individual leaf is assumed to be equal or greater than that of wheat. The photosynthetic ability of sago and oil palms leaves is very important for understanding why sago and oil palms have high productivity in spite of a low nutrient environment.  相似文献   

14.
Remote sensing is increasingly used by policy-makers and conservationists to identify conservation priorities and changes in land cover. This is particularly important in the biodiverse tropics, where there are often few field data. Conservation action is often directed towards areas containing globally threatened species, but there have been few attempts to improve assessments of species’ extinction risk through remote sensing. Here, in a novel approach we use deforestation estimates, measured through satellite imagery, to assess the conservation status of an entire endemic avifauna, based on IUCN Red List criteria. The island of New Britain, east of New Guinea, is of very high global conservation importance, and home to 37 endemic or restricted-range bird species. Analysis suggests 12% of forest cover was lost between 1989 and 2000, including over 20% of forest under 100 m altitude, with substantial areas cleared for commercial oil palm plantations. Application of the IUCN Red List criteria to these new data on area of remaining forest and rates of deforestation indicates that many species are more threatened than previously realised, with the total number of threatened or near threatened species increasing from 12 to 21. Thus, this study highlights the urgency of establishing and effectively managing protected areas in suitable lowland forests of New Britain. More broadly, it demonstrates another potential of remote sensing to assist strategic conservation decisions.  相似文献   

15.
Tropical mammals represent some of the most threatened species, but also the least known because they tend to be difficult to study. To objectively evaluate the conservation status of these species, standardized methods are urgently required. The sun bear Helarctos malayanus is a case in point: it is cryptic, difficult to detect and consequently classified on the IUCN Red List as Data Deficient, and the highest priority for bear conservation research. In this study, we apply a detection/non-detection sampling technique using camera trap data with environmental covariates to estimate sun bear occupancy from three tropical forest study areas with different levels of degradation and protection status in Sumatra. Sun bear detections, and encounter rates, were highest in one of the primary forest study areas, but sun bear occupancy was highest in the degraded forest study area. Whilst, sun bears were recorded at a greater proportion of camera placements in degraded forest, these records were often on only one occasion at each placement, which greatly increased the final occupancy estimate. Primary forests with their large fruiting trees undoubtedly represent good sun bear habitat, but our results indicate that degraded forest can also represent important habitat. These forests should therefore not be considered as having limited conservation value and assigned to other uses, such as oil palm production, as has previously happened in Sumatra. Estimating occupancy between years will yield information on the population trends of sun bears and other tropical mammals, which can be used to provide more reliable conservation assessments.  相似文献   

16.
During repeated deep-fat frying of potato slices at 163 degrees C in yellow or red palm olein of comparable fatty acid profiles, the oxidative stability (peroxide value and anisidine value) of the palm oleins was similar, and in yellow palm olein, the rate of antioxidant depletion decreased in the order gamma-T3 > alpha-T3 > delta-T3 (T3, tocotrienol). In red palm olein, which had a total tocopherol/tocotrienol content of 1260 vs 940 ppm in yellow palm olein and a corresponding longer induction period in the Rancimat stability test at 120 degrees C, only depletion of gamma-T3 was significant among the phenols during frying and slower as compared to that in yellow palm olein. The carotenes in the red palm olein were depleted linearly with the number of fryings, apparently yielding an overall protection of the phenols. In antioxidant-depleted palm olein and in phospholipid liposomes with added increasing concentrations of phenols, gamma-T3 was found to be a better antioxidant than alpha-T3. alpha-T3 and alpha-T (T, tocopherol) had a similar antioxidant effect in antioxidant-depleted palm olein in the Rancimat stability test, while in the liposomes the ordering as determined by induction period for the formation of conjugated dienes was gamma-T3 > alpha-T3 > alpha-T. The addition of 100-1000 ppm beta-carotene to antioxidant-depleted palm olein or liposomes (lycopene also tested) did not provide any protection against oxidation. In the liposomes, synergistic interactions were observed between beta-carotene or lycopene and alpha-T, alpha-T3, or gamma-T3 for carotene/phenol ratios of 1:10 and 1:2 but not for 1:1. In chloroform, carotenes were regenerated by tocopherols/tocotrienols from carotene radicals generated by laser flash photolysis as shown by transient absorption spectroscopy, suggesting that carotenes rather than phenols are the primary substrate for lipid-derived radicals in red palm olein, in effect depleting carotenes prior to phenols during frying. Regeneration of carotenes by the phenols also explains the synergism in liposomes. In the laser flash photolysis experiments, gamma-T3 was also found to be faster in regenerating carotenes than alpha-T3 and alpha-T.  相似文献   

17.
This work was realized in two Tunisian continental palm plantations (Deglet Nour). It aimed at studying the mineral composition of date palms' leaflets to base recommendations for foliar diagnosis on.

At pollination, three palms per palm tree were taken at the median position, the lower green palm, and the last open palm. Leaflets were analyzed on the entire palm split into 4 zones. A broad variation of the palm portions leaflets' mineral composition is shown. The median zone leaflet nitrogen (N) and magnesium (Mg) contents were the highest for all of the palm positions. A similar nitrogen and magnesium determination was noticed along each palm.

The highest calcium (Ca) content was at the base of the youngest palm and at the apex of the oldest palm; phosphorus (P) content was the reverse. The highest potassium (K) content was determined in the base palm leaflets.

For foliar diagnosis, median zone leaflet sampling of median palm at pollination is recommended.  相似文献   

18.
The endemic palm civet Macrogalidia musschenbroekii of Sulawesi (formerly Celebes) is considered rare and among the least known of carnivores. Information gathered over a 30-month period in Northern and Central Sulawesi revealed that it coexists with the more abundant Malay civet Viverra tangalunga, but occurs chiefly in primary forest from sea level to Upper Montane Rain Forest and Elfin Forest. The Malay civet is associated primarily with villages, cultivated land, and secondary growth, as well as primary forest. The species are distinguishable by animal signs such as tracks, latrines, and tree scratchings. Scat analysis and feeding trials with captive civets reveal that Macrogalidia feeds mainly on small mammals and fruit, especially of palms, while Viverra feeds predominantly on small vertebrates with a more selective appetite for fruit. Circumstantial evidence suggests that individual Macrogalidia range over relatively large areas. The species appears to be neither abundant nor scarce. Lowland populations of Macrogalidia could be strongly affected by timber cutting and land cultivation, but there is no immediate threat to montane habitats.  相似文献   

19.
Knowledge of the effects of farmer practices on population genetic parameters of peach palm (Bactris gasipaes Kunth) is relevant to the improvement and conservation of the palm’s genetic resources. Microsatellite markers were used to assess genetic diversity and population structure of peach palm in swidden-fallow agroforestry systems in northeastern Peru. The study covered eight communities, comprising two study areas 160 km apart – one occupied by indigenous Amerindians and the other by mixed race campesinos. Simultaneous analysis of an ex situ peach palm germplasm collection provided a means to compare population genetic parameters. Farmers who were surveyed on seed selection practices for peach palm reported that an average of only four palms (4.3 for campesino and 1.5 for indigenous populations) were used to provide seed for the establishment of the forest gardens sampled. As expected, inbreeding coefficients observed within communities were relatively high (f = 0.105 − 0.210), however, observed heterozygosities within communities were also high (0.625–0.741). A metapopulation approach was used to describe migration within and among regions, implying a hierarchical structure of gene flow which maintains relatively high levels of genetic diversity. Seed migration was found to occur over longer distances (≤600 km) and at a higher frequency (46% of palms sampled) in the indigenous study area, and a proportionally greater number of alleles was found (49 vs. 43 over three loci) with twice as many private alleles occurring only in the indigenous populations. The farmers’ practice of preserving remnant palms through successive swidden generations may have contributed to the maintenance of alleles by reducing the severity of founder effects. Although the campesino study area exhibited a significant (20% of the variation; p < 0.01) isolation-by-distance relationship across 35 km distance, in general, both study populations had relatively limited genetic structure (θ = 0.012–0.03), which is believed to have resulted from the exchange of seeds over long distances and periods of time.  相似文献   

20.
Southeast Asia experiences one of the highest rates of deforestation in the tropics due to agricultural expansion, logging, habitat fragmentation and urbanization, which are expected to result in species declines and extinctions. In particular, growing global demands for food, biofuel and other commodities are driving the rapid expansion of oil palm and paper-and-pulp industries at the expense of lowland dipterocarp forests, further jeopardizing Southeast Asian forest biotas. We synthesize recent findings on the effects of land-use changes on plants, invertebrates, vertebrates and ecosystem functioning/services in Southeast Asia. We find that species richness and abundance/density of forest-dependent taxa generally declined in disturbed compared to mature forests. Species with restricted ranges and those with habitat and foraging specialization were particularly vulnerable. Forest loss also disrupted vital ecosystem services (e.g. crop pollination). Long-term studies are needed to understand biotic sustainability in regenerating and degraded forests, particularly in the context of the synergistic or additive effects of multiple agents of biodiversity loss (e.g. invasive species and climate change). The preservation of large tracts of mature forests should remain the principal conservation strategy in the tropics. In addition, reforestation and reintroductions of native species, as well as improved connectivity among forest patches could enhance the conservation value of forest remnants in human-dominated landscapes.  相似文献   

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